<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        const obj = {
            uname : 'ikun'
        }

        Object.defineProperty(obj, 'age', {
            value : '6',
            writable : true, //默认值为false，可读写的意思
            enumerable : true, //默认值为false,可枚举遍历的意思
            configurable : true, //默认值为false,不可变性的意思，为true可以删除

        })
        
        obj.age = 12
        obj.age = 18
        // delete obj.age
        console.log(obj)
    </script>
</body>
</html>